Im a new fan of Sti's and I see alot of talk of this "stage 2" upgrade for the Sti basically I just wanna know what this consists of, and how much it usually costs. And lastly the results of the upgrade.
A turbo-back and a tune. The price range is wide depending on how you get the turbo back and a tune. The easiest way is just to buy the cobb tuning stage 2 kit for around 1,800. The cheap method would be to get an inexpensive turboback and tune the car yourself with free programs like enginuity and an ODBII to usb cable using stage2 maps that people have uploaded.
EDIT: results would be around 40hp, maybe more maybe less depending on the car year and such.